Perhaps you should try some spelling variations:
"improving poor performance metrics." » "improving poor performance measures.", "improving sector performance metrics.", "improving power performance metrics.", "improving food performance metrics.", "improving peer performance metrics."
"improving country performance series." » "improving country performance studies.", "improving country performance size.", "improving voluntary performance series.", "importing country performance series.", "improving community performance series."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving country performance series.") or ("improving poor performance metrics."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving country performance series.") OR ("improving poor performance metrics.")).
• Removing quotes may allow a broader search: (( improving country performance series. ) or ( improving poor performance metrics. )).
• Adding a wildcard symbol may retrieve word variants: (("improving country performance series.") or ("improving poor performance metrics."))*.